FR2957939A1 - Modular injector to inject gas in treatment chamber, comprises injectors including inlet to receive gas wave, curved section to dilate gas in direction perpendicular to propagation axis of gas and outlet to eject gas, and connection zone - Google Patents

Abstract

The modular injector (11) comprises injectors including an inlet for receiving a gas wave or a gas pulse, a curved section (20) for dilating the gas in a direction perpendicular to a propagation axis of the gas and an outlet for ejecting the gas, and a connection zone. The section includes first and second walls (23), which diverge according to an angle of divergence with respect to the gas propagation axis. The connection zone extends between walls, and includes a unit for ejecting the gas in the vicinity of the connection zone. The modular injector (11) comprises injectors including an inlet for receiving a gas wave or a gas pulse, a curved section (20) for dilating the gas in a direction perpendicular to a propagation axis of the gas and an outlet for ejecting the gas, and a connection zone. The section includes first and second walls (23), which diverge according to an angle of divergence with respect to the gas propagation axis. The connection zone extends between walls, and includes a unit for ejecting the gas in the vicinity of the connection zone at a rate greater than the ejection of gas near the center of the outlet to compensate the lack of gas ejected in the connection zone. The gas ejected by the outlet has a velocity profile with a variation of less than 90%. The injectors further include a diffusion plate including openings for the passage of gas, a constriction region, a first dilation region (25) in which the walls diverge according to a first angle of divergence, and a second dilation region (26) in which the walls diverge according to a second angle of divergence, which is lower than the first divergence angle. A height of the section varies according to an axis perpendicular to the propagation axis. The constriction region has a first height close to the center of the section and a second height close to the wall. The first height is lower than the second height so as to slow down the velocity of the gas close to the center of the section and the wall. The first angle of divergence varies with the second angle of divergence, and has a maximum value at the end of the first region. Independent claims are included for: (1) a system for depositing thin layers in an injector; and (2) a process for injection of a gas wave or a gas pulse in a treatment chamber.

Description

MODULAR GAS INJECTION DEVICE

The present invention relates to a gas injection device and a method for injecting a gas into a treatment chamber. The present invention more particularly relates to a method for injecting a gas into a treatment chamber of a thin-film reactor. Thin layer deposition techniques, for example physical vapor deposition (PVD) and chemical vapor deposition ("CVD"), are techniques for depositing thin layers on a substrate, for example a semiconductor substrate. A particular example of CVD is atomic layer deposition "ALD" ("Atomic Layer Deposition"), also referred to as "ALE" ("Atomic Layer Epitaxy") or "ALCVD" ("Atomic Layer Chemical Vapor Deposition"). This process is used for the manufacture of semiconductors and the manufacture of thin film magnetic heads. It is currently envisaged to use this method for the manufacture of various new devices, for example organic light emitting diodes (OLEDs) and photovoltaic elements. FIG. 1A shows a conventional thin film deposition system TFS1 comprising at least one injector 1 with a flow shaping section 2, a treatment chamber 4 in which a substrate 5 can be arranged, and a device for discharge 6. A gas tube 7 connects the injector 1 to at least one gas source 8. During the deposition process, a carrier gas comprising reactants is generally introduced into the injector 1 for a certain period of time, 35 thus forming a "gas wave" or "gas pulse".

As described in US Pat. No. 7,163,587, the shaping section 2 of the injector may have a triangular shape with first and second walls diverging at a constant divergence angle with respect to a propagation axis XX 'of the injector. gas wave in the injector. The shaping section 2 laterally expands the gas wave during its passage from a point 0 to the inlet of the shaping section 2 until it reaches the injector outlet which gives The gas is then injected into the treatment chamber 4, as shown in FIG. 1A by the arrows. In the treatment chamber, reactants in the gas may react with the surface of the substrate 5 and / or with previously deposited molecules. The treatment chamber 4 can then be purged by injection of an inert gas which discharges all reactants and excess products from the system, by means of the evacuation device 6. The pulse / purge steps can then be repeated with a second gas from another source of gas. Thin layers, for example between 0.1 and 3 Å, are formed on the substrate 5. This cycle is repeated as many times as necessary to obtain the desired thickness of the thin layer.

Due to its layer-by-layer implementation, an atomic layer deposition achieves a very high structural quality and a very good control of the thickness of the thin layers, as well as a good recovery of any element present on the substrate.

Nevertheless, because of the pulse and purge steps, the duration of this process can be from a few minutes to several hours, depending on various factors such as the thickness of the desired thin layer, the reactants used, the duration of the cycles, etc., resulting in a relatively low production capacity. of the

Recent research and developments have focused on reducing the deposition time of thin films to make this technique more interesting in the context of large-scale manufacturing.

To decrease the cycle time, it is usual to increase the gas flow. However, because of the Poiseuille law, the triangular shape of the shaping section makes the gas in the center of the injector reaches the outlet before the gas in the vicinity of the walls.

Therefore, when such an injector is used in an application where a time-sequential composition profile is created at the input, this peak velocity distribution becomes a non-uniform gas composition distribution, which slows the process by increasing the time required for a gas wave to pass through the treatment chamber, as will be explained in connection with Figures 1B, 1C. FIG. 1B represents the profile C01 of the velocity V of the gas, expressed in meters per second, at the outlet of the injector 1 of FIG. 1A. The velocity of the gas is measured along an axis YY 'perpendicular to the axis of propagation XX'. It may be noted that the profile C01 of the gas velocity has a maximum value at the point O 'at the center of the outlet of the injector, and decreases rapidly while moving away from the point 0', to reach 0 in the vicinity of the walls. of the injector. FIG. 1C shows two profiles P01, P02 for concentration of the gas GC along the axis of propagation XX 'through the treatment chamber 4, starting from the point 0' at the outlet of the injector, at two different times after the injection of the gas wave. The gas concentration is expressed as a percentage of the reactant present in the gas per unit volume. It can be noted that, thanks to the diffusion of the reactant in the carrier gas, the length of the wave or

the gas pulse increases as it passes through the treatment chamber. In the light of FIGS. 1B and 1C, it will be understood that a relationship exists between the length of the gas wave P01 and the velocity profile of the gas C01. The increase in the non-uniformity of the velocity profile along the axis YY 'at the outlet of the injector causes an increase in the time to evacuate the gas from the injector, an increase in the length of the profile of the injector. gas wave along XX 'which passes through the treatment chamber, and an increase in the time required between the injection of two successive gas pulses, since the part of the slowest gas wave must be removed from the chamber before the injection of the next wave.

Nonuniform gas distribution can also lead to deposition anomalies and irregularities in the thin layers. Therefore, it may be desired to have a gas distribution across the substrate as uniform as possible. The gas wave should be optimized for the thin film deposition system and is closely related to the physical properties of the injectors, the dimensions of the treatment chamber, the substrate on which the deposition will be made, etc. Since thin film deposition systems are typically used for electronic applications, they are, in general, optimized for standard substrate sizes commonly used in this industry, for example diameters of 150, 200 and 300 mm. In order to apply these techniques to larger substrates in other fields of application, the dimensions of the injectors, the gas inlets, the treatment chamber, the evacuation device, etc. need to be suitably modified, which complicates and increases the cost price of thin-film deposition systems for large substrates (500 mm or more) with

very short cycle. It is neither practical nor economical to develop a system for every possible combination of treatment, and current systems are not well suited to large substrates, which limits their utility for other areas of application. In addition, recent interest has emerged in the application of thin film deposition methods to other industries, such as the deposition of layers on glass, the production of displays, and the production of photovoltaic elements. These applications use much larger substrates, for example 1200 x 600 mm glass plates or a continuous roll of flexible material, which requires an increase in the amount of gas passing through the injector and an expansion of the outlet. of the injector. However, the increase of the gas flow rate and the widening of the injector outlet cause turbulence and recirculation of the gas in the injector, resulting in a distribution of the gas on the surface of the substrate even less uniform, and a purge of reactants from the inefficient system. Embodiments of the present invention provide a modular injector for injecting gas into a process chamber. According to one embodiment, the injector comprises at least two adjacent injectors, each injector comprising: an inlet for receiving a gas wave or a gas pulse; a shaping section having left and right walls diverging at an angle of divergence from an axis of propagation of the gas, for expanding the gas in a direction perpendicular to the axis of propagation; and an outlet for ejecting the gas, the modular injector forming a substantially equivalent large injector having a large equivalent output including the outlets of the adjacent injectors and expanding the gas over the large equivalent output. According to one embodiment, the modular injector comprises a connection zone extending between adjacent walls of the injectors, in which each injector neighbors important to compensate connection. According toconfigured comprises means for ejecting the gas at the connection zone with a flow rate more than near the center of its outlet, in order to the lack of gas ejected in the zone of

one embodiment, the injectors are such that the gas ejected by the modular injector through the large equivalent output has a velocity profile with a variation of less than 10% between the maximum and minimum velocities over at least 90% of the width of the large equivalent output, at a determined distance from the output and the connection area. According to one embodiment, each injector comprises a diffusion plate comprising a plurality of openings for the passage of the gas, the openings being dimensioned and / or spaced apart from each other so that the injector ejects the gas in the vicinity of the connection area with a higher flow rate than near the center of its exit. According to one embodiment, the shaping section of each injector comprises at least one constriction region in which a height of the shaping section varies along an axis perpendicular to the axis of propagation and has a first height to near the center of the shaping section and a second height near the wall near the connection area, the first height being less than the second height to reduce the velocity of the gas near the center relative to the gas velocity to the wall in the vicinity of the connection zone.

According to one embodiment, the shaping section of each injector has a first expansion region in which the walls diverge at a first divergence angle, and a second expansion region comprising the constriction region, in which the walls diverge. at a second divergence angle smaller than the first divergence angle, to increase the gas velocity in the vicinity of the walls near the connection area with respect to the velocity of the gas near the center of the shaping section. According to one embodiment, the first angle of divergence varies and has a maximum value at the end of the first region, and the second angle of divergence is constant and less than the maximum value of the first angle of divergence. According to one embodiment, the modular injector has a curved shaping section. Embodiments of the invention also relate to a system comprising a processing chamber; at least one modular injector according to the modular injector described above, the large equivalent output of which gives on the treatment chamber; and at least one gas source coupled to the inlet of the injectors of the modular injector. According to one embodiment, the system comprises at least two superimposed modular injectors arranged such that each injector of each modular injector has a common output with an injector of the other modular injector. Embodiments of the invention also relate to a method for injecting a gas wave or a gas pulse into a process chamber, comprising the steps of: expanding the gas in a direction perpendicular to an axis of propagation of the gas; and inject the gas into the treatment chamber. According to one embodiment, the method comprises the step

of injecting the gas into the treatment chamber by means of a modular injector comprising at least two adjacent injectors, each injector comprising an inlet for receiving a gas, a shaping section having left and right walls which diverge according to a divergence angle with respect to the axis of propagation of the gas, for expanding the gas in a direction perpendicular to the axis of propagation, and an outlet for ejecting the gas, the modular injector forming a large equivalent injector having a large output equivalent comprising the outlets of the adjacent injectors and expanding the gas over the large equivalent outlet. According to one embodiment, the modular injector comprises a connection zone extending between adjacent walls of the injectors, and the method comprises a step consisting in configuring each injector so that it ejects the gas in the vicinity of the connection zone. with a higher flow than the center of its output, to compensate for the lack of gas ejected in the connection area. According to one embodiment, the method comprises a step of configuring each injector such that the gas ejected by the modular injector has a velocity profile with a variation of less than 10% between the maximum and minimum speeds over at least 90 % of the width of the large equivalent output. According to one embodiment, the method comprises a step of providing, in each injector, a diffusion plate having a plurality of openings for the passage of gas, the openings being dimensioned and / or spaced from each other such that the injector ejects the gas in the vicinity of the connection zone with a greater flow rate than near the center of its outlet.

According to one embodiment, the method comprises a step of providing, in the shaping section of each injector, at least one constriction region in which a height of the shaping section varies along an axis. perpendicular to the axis of propagation of the gas and has a first height near the center of the shaping section and a second height near the wall of the shaping section near the connection area, the first height being lower than the second height to reduce the velocity of the gas near the center of the injector relative to the velocity of the gas near the wall near the connection zone. Embodiments of the invention will be described in the following with reference to, but not limited to, the accompanying drawings in which: - Figure 1A previously described is a schematic top view of a conventional thin film deposition system; FIG. 1B previously described represents a velocity profile of a gas passing through the system of FIG. FIG. 1C previously described represents a concentration profile of a gas that passes through the system of FIG. FIGS. 2A and 2B are schematic side and plan views of a thin film deposition system according to a first aspect of the invention; Figure 3 is a top view of a first embodiment of an injector of the system shown in Figures 2A, 2B; - Figures 4A, 4B, 4C, 4D are sectional views of the injector of Figure 3 according to different cutting planes; FIGS. 5A, 5B, 5C, 5D represent different velocity profiles of a gas which passes through the injector of FIG. 3, at different points of the injector; FIG. 6 represents variations in a speed profile of a gas at an outlet of the injector of FIG. 3, for different gas inlet speeds; FIG. 7 represents different concentration profiles of a gas that passes through the system represented on the 2A, 2B; - Figure 8 is a sectional view of an assembly of injectors of the system shown on 2A, 2B; FIG. 9 is a perspective view of a second embodiment of an injector of the system represented on the 2A, 2B; FIG. 10 is a schematic view of a first embodiment of a thin film deposition system according to a second aspect of the invention; FIG. 11 is a schematic view from above of a second embodiment of a thin film deposition system according to the second aspect of the invention; FIGS. 12A and 12B show diffuser plates present in the system of FIG. 11; FIG. 13 is a schematic view from above of a third embodiment of a thin film deposition system according to the second aspect of the invention; FIG. 14 represents the velocity profile of a gas passing through the system of FIG. 13; and FIGS. 15A, 15B, 15C show different gas circuit arrangements of a thin film deposition system according to the invention. One embodiment of a TFS2 thin film deposition system according to a first aspect of the invention is schematically shown in Fig. 2A (side view) and Fig. 2B (top view). For reasons of clarity of the drawings, the elements are not

necessarily shown to scale and the drawings do not necessarily show every aspect of the system. The TFS2 system is designed for atomic layer deposition and comprises an injector assembly 10 having two injectors 11, 11 ', a base unit 40, and an evacuation device 60. The base unit 40 includes a chamber processor 41 receiving a substrate 50 which can be mounted on a support. Each injector 11, 11 'has a gas inlet inlet connected to a gas source 81, 82 through a gas tube 71, 72 and a valve 85, 86. The base unit 40 may be made of metal, for example aluminum or stainless steel, and may include other components, such as components for creating a vacuum, for heating the treatment chamber and / or the substrate, openings for the introduction and removing the substrate, cleaning, aligning the base unit with other components, etc. A first gas wave is introduced into the injector 11 and propagates along a propagation axis XX 'through the injector 11, in which it is expanded laterally, that is to say along an axis Y4Y4' perpendicular to the propagation axis XX ', before being injected into the treatment chamber 41. In the treatment chamber, the first gas wave passes through the surface of the substrate 50 into a wave which is substantially parallel to the surface of the substrate, and reacts with the substrate before being purged from the chamber by means of the evacuation device, which is connected to a pump 60. A second gas wave is then introduced into the injector 11 'and propagates along the XX 'propagation axis through the injector 11', wherein it is laterally expanded along the axis Y4Y4 'before being injected into the treatment chamber 41. In the

processing chamber, the second wave of gas passes through the surface of the substrate 50 in a wave which is substantially parallel to the surface of the substrate, and reacts with deposits left by the first gas injection. By way of example, to obtain an Al 2 O 3 layer, a first gas comprising aluminum (for example trimethyl aluminum TMA or AlCl 3 aluminum chloride) is pulsed through the first injector into the treatment chamber where it reacts with the substrate. Then, the first gas is purged from the chamber by means of the evacuation device while an inert gas, such as nitrogen N2 or argon Ar, is introduced into the chamber by means of the first injector. Then, a second gas comprising oxygen (for example H20 water vapor or ozone 03) is pulsed into the chamber through the second injector, and the oxygen reacts with the aluminum, forming a monolayer Al203. The chamber is still purged with an inert gas, and the cycle is repeated. Figure 3 is a top view showing in more detail the structure of the injector 11 according to a first embodiment of the invention. It is assumed that in this embodiment the two injectors 11, 11 'have the same structure. As a result, only the injector 11 will be described. Nevertheless, other embodiments may be provided, wherein the injectors 11, 11 'have different structures, for example depending on the nature of the gas they eject. The injector 11 comprises a body 12 and a shaping section 20. The shaping section 20 may be a countersunk cavity of the body 12. The body may be a metal plate, for example aluminum or stainless steel . The cavity can be formed by milling

accurate of the metal plate. A cover 13 (not shown in FIG. 3) can be assembled to the body 12 by welding, or brazing, or simply mounted on it by means of screws, dowels, etc.

The shaping section 20 includes an inlet 21 and an outlet 22. The inlet 21 is connected to the gas tube 71 and has the shape of a small opening. The outlet 22 has the shape of a larger opening and gives access to the treatment chamber for injecting the gas therein. The shaping section comprises left and right walls 23, a lower surface, and an upper surface formed for example by the lid mentioned above. The lower and upper surfaces are substantially parallel except in a region to be described below. The walls 23 diverge outwardly from the inlet 21 to the outlet 22, expanding the gas wave in a direction perpendicular to a propagation axis XX 'of the gas wave. The shaping section 20 further includes a constriction region 24 for shaping the gas velocity profile as desired. As will be explained below, the height of the shaping section 20 in the constriction region 24 varies to uniformize the gas wave velocity over the entire lateral expansion width of the injected gas wave. in the processing chamber 41. The injector 11 thus expands the gas wave along the axes Y1Y1 ', Y2Y2', Y3Y3 ', Y4Y4' perpendicular to the axis of propagation XX ', while adjusting the speed of the gas on the entire width of lateral dilation. In particular, and as shown in FIG. 4C, the constriction region may have a reduced height h2 in the vicinity of the propagation axis and a greater height h3 in the vicinity of the walls 23, in order to reduce the speed of the gas in the vicinity. from the center of the shaping section relative to its speed near the walls.

In the embodiment shown in Fig. 3, the shaping section further comprises a first expansion region 25 which achieves only a lateral dilation and a second expansion region 26 which includes the constriction region 24 and performs an expansion. lateral and vertical constriction (regions 25, 26 are indicated by different shades). The first expansion region 25 extends from the inlet 21 to a transition point X2, and the second expansion region 26 extends from the point X2 to the outlet 22. The first and second expansion regions can consist of two different parts connected together, or simply be different parts of one piece. The first expansion region 25 includes a left wall 23a and a right wall 23b, and the second expansion region 26 comprises a left wall 23c and a right wall 23d. The walls 23a, 23b of the first expansion region 25 diverge at a divergence angle A1 with respect to the propagation axis XX 'of the gas wave, while the walls 23c, 23d of the second expansion region 26 diverging at an angle of divergence A2 with respect to the axis of propagation XX '.

In one embodiment, the angle of divergence A1 is greater than the divergence angle A2, so that the second expansion region 26, while achieving overall lateral expansion of the gas wave, also performs an additional function. constricted in the vicinity of the walls to further reduce the velocity of the gas near the center relative to its velocity in the vicinity of the walls of the second expansion region 26. In one embodiment, the divergence angle Al varies. and increases with increasing distance

from the input 21, to reach a maximum value Almax at the end of the first expansion region 25, while the divergence angle A2 is constant, Almax being greater than A2. Preferably, the angle of divergence A1 varies according to a "supralinear" function, for example a quadratic or exponential function. A supralinear lateral dilation promotes the suppression of turbulence near the inlet 21 of the injector 11, where the gas velocity is the highest.

In the embodiment shown in FIG. 3, the walls 23a, 23b of the first expansion region 25 exponentially diverge while the walls 23c, 23d of the second expansion region 26 diverge linearly with a constant angle A2.

FIGS. 4A, 4B, 4C, 4D show sectional views of the injector of FIG. 3 in different sectional planes, respectively P1, P2, P3, P4, which are perpendicular to the propagation axis XX '. The plane P1 passes through a point X1 of the axis XX ', the point X1 being situated at a distance d1 from a reference point 0 to the input 21. The plane P2 passes through a point X2 of the axis XX X2 being at a distance d2 from the point 0, the distance d2 being greater than the distance d1 and equal to the length of the first expansion region 25. The plane P3 passes through a point X3 of the axis XX ', the point X3 being located at a distance d3 from the point 0, the distance d3 being greater than the distance d2 and substantially corresponding to the central point of the constriction region 24. The plane P4 passes through a point X4 of the axis XX X4 is located at a distance d4 from the point 0, the distance d4 being greater than the distance d3 and equal to the length of the shaping section 20, so that the plane P4 includes the output 22 of the injector. In FIG. 3, the propagation axis XX 'and a longitudinal axis of symmetry of the injector are

together, so that the points X1, X2, X3, X4 are each equidistant from the left and right walls of the shaping section 20. In Figure 4A, the sectional view of the first expansion region 25 of the Shaping section 20 has a substantially rectangular shape, with a width W1 and a height h1. The height h1 is the distance between the lower surface and the upper surface of the shaping section 20, the upper surface being constituted by a lower face of the cover 13. In FIG. 4B, the sectional view of the section at the boundary between the first and the second expansion region 25, 26, has a substantially rectangular shape with a width W2> W1 and a height h1 equal to that of FIG. 4A. In FIG. 4C, the sectional view of the shaping section 20, in the constriction region 24 located in the second expansion region 26, has a width W3> W2, a flat upper surface and a substantially convex lower surface. . It therefore has a first height h2 in the center of region 26 (that is to say in the vicinity of point X3) and a second height h3 close to the walls, where h3 is greater than h2 in order to reduce the speed of gas in the center of the second expansion region with respect to the velocity of the gas near the walls. In one embodiment, the shape of the convex lower surface along the axis Y3Y3 'is defined according to a Bézier curve.

In this embodiment, h2 is greater than h1 but may be less than or equal to h1 in other embodiments. In FIG. 4D, the sectional view of the shaping section 20, near the outlet 22, has a substantially rectangular shape with a width

W4> W3 and a height h4 less than h3 and also less than h1. In other embodiments, h4 may be greater than h1 and less than h2. In one embodiment, the lower surface of the second expansion region 26 comprises two surfaces defined by "non-uniform Rational Basis Spline" (NURBS), one in the area between axes Y2Y2 'and Y3Y3', and another in the area between the axes Y3Y3 'and Y4Y4'.

FIGS. 5A, 5B, 5C, 5D represent different profiles C1, C2, C3, C4 of velocity V of a gas wave which passes through the injector, measured along different perpendicular axes YlYl ', Y2Y2', Y3Y3 ', Y4Y4' to the propagation axis XX 'and respectively included in the planes P1, P2, P3, P4. A digital fluid mechanics analysis (MFN) on a discrete three-dimensional model of injector geometry using the finite volume method can be used to obtain such profiles.

It may be noted that: - In FIG. 5A, the profile C1 is very sharp around the central point X1 of the shaping section 20 and has a high speed (for example 17 m / s) at this point, then it decreases rapidly moving away from point X1 to reach a velocity of 0 m / s in the vicinity of walls 23 (the velocity of a gas passing through a pipe always being equal to 0 just next to the walls of the pipe); In FIG. 5B, the profile C2 is always pointed, but less, around the central point X2, has a lower speed (for example 5 m / s) at the point X2, and decreases less rapidly than the profile C1 when moving away. from the central point X2, to reach a speed of 0 m / s in the vicinity of the walls 23;

- In Figure 5C, it can be noted that the correction of the speed distribution between the center of the injector and the walls has begun. The profile C3 is no longer sharp around the central point X3, and has a fairly flat profile with steep slopes in the vicinity of the walls 23. The higher height h3 generates a reduced resistance of the flow near the walls, leading the gas to edges. As a result, the gas has a higher speed of about 10% near the edges with respect to the center. The profile C3 thus has a small "hollow" in the vicinity of the central point S3 and two "bumps" on each side of the hollow; and - In FIG. 5D, the profile C4 is substantially uniform over the majority of the outlet 22 and decreases abruptly at a speed of 0 m / s in the vicinity of the walls 23. Consequently, the different heights h1, h2, h3, h4 of the injector can be adjusted to adjust as desired the speed profile of the gas injected into the treatment chamber. In applications where a uniform velocity profile is desired at the nozzle exit, the present invention provides a velocity distribution of less than 10% between the maximum and minimum speeds over at least 90% of the width of the nozzle. exit. Generally, the velocity distribution at the outlet 22 of the injector depends not only on the difference between h1, h2, h3, h4, but also on the difference between the maximum divergence angle Al of the first expansion region 25 and the angle of divergence A2 of the second expansion region 26, and also the initial velocity of the gas at the inlet 21, as will be demonstrated with reference to FIG. 6. FIG. 6 shows the effect of the velocity of the input gas 35 on the velocity profile of the gas at the exit of

the injector 11 along the axis Y4Y4 '. The gas velocity is expressed here as a ratio between the gas velocity along the Y4Y4 'axis and its maximum velocity. In this example, the first expansion region 25 has a width W2 of 10 cm, a length d2 of 7.5 cm, and an angle of divergence A1 which varies exponentially. The constriction region 26 has a height h3 = 0.5 * h2. Three profiles C4 ', C4 ", C4"' are represented and correspond to the input speeds 21, respectively 10 m / s, 40 m / s, 70 m / s. The profiles C4 'and C4 "have two lateral" bumps "and a central" hollow ", and therefore have the lowest speed near the central point X4 and the two highest points near the walls. has three "bumps" and two "hollows", and therefore a center point and two maximum speed lateral points, and two minimum speed points between the maximum speed points. It will be appreciated that these speed profile characteristics are shown in an exploded view and are, in practice, of relatively small dimensions. For example, for the profile C4 "', the difference between the" bumps "and the" hollows "represents a variation of less than 1% of the gas velocity, which is therefore substantially uniform over most of the width of the exit. These profiles demonstrate that, for a given shape of the expansion regions 25, 26 and the constriction region 24, a critical speed VC exists.The behavior of the injector differs depending on the speed of entry of the injector. At the inlet of the injector, depending on whether it is below or above the critical velocity V. Below the critical velocity, there is no turbulence and recirculation in the first expansion region 25, the velocity profile is substantially constant and independent of the

entry speed. Above the critical speed, recirculation occurs in the first expansion region 25, and the output velocity profile changes with the input velocity, causing changes in the uniformity of the velocity profile. The value of the critical velocity VC depends on the geometry: a first short and / or wide expansion region has a lower critical velocity VC, which means that recirculation or turbulence occurs at a lower input velocity relative to a longer and / or narrower expansion region. As a result, there is an approximate relation of the type VC = f (d2 / W2). The output velocity profile can be adjusted by adjusting the height h2 of the constriction region at the point X2. The correction required depends on the length of the first expansion region 25 and the desired operating point. A method of designing the injector may consist of a slight overcompensation of the speed in the vicinity of the walls so that its most uniform speed profile is at the highest input speed before reaching the critical speed. In general, those skilled in the art have the ability to adjust the properties of the injector, for example by modifying the heights h1, h2 h3, h4 to obtain the desired gas profile in connection with an application. considered. The height h1 may be chosen to correspond approximately to the diameter of the gas inlet tube, which may have a standard diameter of 6 mm or about 12 mm, in some applications. If a height h1 is chosen so that it is significantly different from the diameter of the inlet, a step in the path of the gas can be created, which generates recirculation or turbulence. The height

h4 may be relatively small, for example 1 to 2 mm in some applications, and may be limited by the manufacturing process. A reduced height h4 can help prevent gas reflux from another injector if there is more than one injector. FIG. 7 shows profiles P10, P11, P12, P13 of a gas concentration GC along the propagation axis XX 'through the treatment chamber 41, from point X4 to the outlet of the injector (cf. Figure 3), at four moments after injection of the gas wave into the injector, respectively, 80 ms, 100 ms, 120 ms and 140 ms. The gas concentration is expressed as a percentage of the reactant present in the gas per unit volume (for example TMA or oxygen). During the propagation of the gas wave through the treatment chamber, the gas wave remains very uniform, without losing much of its height or becoming very dispersed. This is due to the initial uniformity of the gas velocity profile at the outlet of the injector. The width of the wave pulse increases slowly, with a slight difference between the values near the walls relative to the values near the center of the injector. It has been observed that the thin film deposition system is ready to begin the next cycle after the purge of the half of the treatment chamber contrary to a conventional method such as that described by US Patent 7,404,984, in which a pulse purge of at least twice the volume of the treatment chamber must be injected before starting the next cycle. Therefore, the monitoring of the speed profile, thanks to the structure of the injector according to the invention, allows an increase in the rate of pulses and purge cycles. FIG. 8 represents a sectional view of an embodiment of the TFS2 thin film deposition system.

shown in Figures 2A, 2B, which illustrate how two injectors 11, 11 'can be assembled to form an injector assembly 10. As previously described, each injector 11, 11' comprises a machined body 12 in which the different regions 24 , 25, 26 of the shaping section 20 have been formed, and a cover 13. A divider block 87 is arranged between the injectors 11, 11 'to form a physical support. Each injector is arranged on the divider block 87 so that its cover 13 is against the divider block. Viewed in section, the divider block has a triangular shape so that each injector 11, 11 'is oriented relative to the other at a given angle, for example 60 °, and their outputs 22 meet to form a common output. The common outlet is formed by a region where their respective bodies 12 are not covered by the cover 13 and are opposite to each other. The injectors 11, 11 'are integral with the base unit 40 and are aligned therewith by means of alignment devices 88, 89, for example pegs. Each injector 11, 11 'is connected at the inlet to a gas tube 71, 72 respectively, which is itself connected to one or more gas sources (not shown).

In another embodiment (not shown), the injectors may not comprise a lid. The divider block 87 can itself form the upper surface of each injector. FIG. 9 represents another embodiment of an injector 111 according to the invention. The injector 111 includes an inlet 112, followed by a first shaping section 113, itself followed by a second shaping section 114, and an exit 115 at the end of the second shaping section. 114. The first shaping section 113 has a curved shape,

substantially S-shaped. It also has walls 116 which diverge at a first angle of divergence A1, preferably a variable angle increasing according to a quadratic or exponential function. Accordingly, the first shaping section 113 forms an expansion device that corresponds to the first expansion region previously described. A propagation axis X1X1 'of the gas here has a curved shape due to the gas passing through the shaped forming section 113 curved. The second shaping section 114 has walls 117 and a constriction region 118 in which its height varies along an axis perpendicular to the axis of propagation X1X1 'of the gas, with a height near its center which is less than the height near the walls 117. In one embodiment, the walls 117 diverge at an angle A2 and the second shaping section 114 corresponds to the second expansion region described above, which includes the constriction region. . In another embodiment, the second shaping section 114 has parallel walls 117 and forms a constriction device for the gas wave ejected by the first shaping section 113, without additional lateral expansion of the gas. It will be appreciated that various other embodiments and applications of an injector according to the invention may be provided by those skilled in the art. The constriction region may have various shapes and may for example be obtained both by variations of the lower surface and the upper inner surface of the shaped section. The constriction region may also be implemented by means of a diffusion plate of the type described below in connection with FIGS. 12A, 12B. These plates include

apertures dimensioned and / or spaced from each other so that in the constriction region the center of the gas wave is slowed relative to its edges.

Furthermore, although it has been indicated above that the TFS2 system is designed for the atomic layer deposition in which waves (or pulses) of gas are injected into the treatment chamber, embodiments of an injector according to the invention can also be used for other processes and other material deposition systems, for example, chemical vapor deposition ("CVD"), physical vapor deposition ( "Physical Vapor Deposition" (PVD), molecular beam epitaxy ("Molecular Beam Epitaxy" MBE), plasma-enhanced chemical vapor deposition ("PECVD"), and more generally, any process wherein a gas passes through an injector and enters a treatment chamber.

Also, the use of the term "substrate" in the description should mean any type of material on whose surface a chemical reaction can occur so that thin layers can be formed. These substrates may be semiconductor material, plastic, metal, glass, optoelectronic devices, flat screens, liquid crystal displays, etc. and can be of various sizes, shapes, and formats. Also, embodiments of an injector according to the invention can also be used to expand a continuous flow of gas instead of forming a gas wave. Such embodiments can improve a thin film deposition process by homogenizing the amount of reactant deposited by the gas.

over the entire treated surface, and therefore uniformize the thickness of the deposited thin film. Also, a thin film deposition system according to the invention may comprise a single injector instead of an assembly comprising two or more injectors according to the invention. In addition, embodiments of an injector according to the invention are not only designed to make the velocity profile of the gas uniform at the outlet of the injector. In other applications, it may instead be desired for the gas velocity in the vicinity of the walls to be different from the gas velocity at the center of the outlet, and in particular it may be desired to obtain a gas velocity greater than adjacent walls relative to the speed in the center of the outlet, which will be demonstrated below in connection with the description of a second aspect of the invention. As indicated above, the application of thin film deposition techniques to treat substrates (500 mm or greater) larger than conventional semiconductor substrates, requires that the dimensions of the injectors, the process chamber, the evacuation device, etc. be adapted accordingly. In such applications, it may be desired to provide a thin film deposition system suitable for large substrates. In this case, it may be desired to provide injectors with a large output. However, it has been observed that the greater the output of an injector, the more difficult it is to control the velocity profile of the gas, i.e. when the ratio of the width of the outlet to the width of the injector the entrance increases. An increase in the width of the outlet while keeping the constant gas velocity at the exit requires that the injector has a greater length than the

the amount of gas required to cross the injector is increased, and the gas is injected at a higher speed at the inlet. All these constraints generate a greater risk of turbulence and recirculation of the gas at the inlet, a less efficient deposition process (longer periods between the injection of successive pulses of gas), a non-uniform gas distribution, anomalies deposition, and irregularities in the thin layers.

Figure 10 schematically shows a top view in section of a thin film deposition system TFS3 according to a second aspect of the invention. The TFS3 system comprises a modular injector 100, a large processing chamber 42 formed to receive a large substrate 52, and a suitable evacuation device 62. The modular injector 100 comprises at least two adjacent injectors, here two conventional injectors 1, 1 ', such as those described in connection with Figure 1A. The two injectors are arranged side by side, and have sidewalls 91 in contact with each other or separated by a seal. Each injector has an inlet coupled to a gas tube 71, 71 'for receiving a gas wave (or a gas flow, according to the method to be implemented), a shaping section 2, 2' having walls left and right diverging at an angle of divergence, and an outlet for ejecting the gas. The modular injector 100 forms a large equivalent injector having a large equivalent output which includes the outputs of the adjacent injectors 1, 1 'and expands the gas on the large equivalent output. The modular injector ejects a gas wave resulting from a juxtaposition of gas waves ejected by each injector, which passes through the processing chamber 42 along a propagation axis X2X2 '.

Such a parallel arrangement of the injectors 1, 1 'avoids the disadvantages indicated above, in particular in that it does not require an increase in the length of the injectors and an increase in the speed of the gas injected at the inlet, thus reducing the associated problems, such as recirculation and turbulence. In practice, the choice of the number of injectors to use depends on the size of the substrate to be treated. In addition, development costs are reduced by optimizing a single injector which is then used as many times as desired to obtain a modular injector. To ensure the generation of a uniform gas wave at the output of the two or more injectors that form a modular injector, different factors must be taken into account, such as the proper alignment of the injectors and the synchronization of the gas waves of all injectors (timing and flow). These factors can be quite easily treated. The alignment of the injectors with each other and with the treatment chamber can be accomplished by any known means, for example positioning pins, rails, etc. Synchronization of gas waves can be accomplished modular component sources. electrically actuated can inject gas pulses of up to 20 ms and a synchronization of several values with an accuracy greater than 1 ms. Another factor that can be considered is the uniformity of the pulse on the large equivalent output of the modular injector. However, with reference to FIG. 10, it may be noted that a connection zone with gas, more precisely by the precise control of the valves, and gas tubes with or less identical for each injector For example, valves pneumatic

90 exists between the injectors, where the two injectors 1, 1 'are connected. The connection zone 90 is defined as a distance between adjacent walls 91 of the outlets of the injectors 1, 1 '. More generally, in a modular injector comprising more than two injectors, it is defined as the distance between adjacent walls of the outlet of any two adjacent injectors. Such a connection zone is generally equal to twice the thickness of the walls of the injectors which are side by side. It may also include the thickness of any alignment or attachment means that can be arranged between two adjacent injectors. It may be further noted that in the absence of gas injection into the connection zone, the gas velocity profile may have a non-uniform region 92 facing the connection zone, along the axis X2X2 'propagation of the resulting gas wave. This phenomenon is aggravated by the fact that conventional injectors 1, 1 'inherently have a non-uniform distribution of gas on their outlets, with a lower gas velocity near the walls. Figure 11 schematically shows a sectional top view of a TFS4 thin film deposition system according to the second aspect of the invention, which provides a better uniformity of the velocity profile of the gas in the processing chamber. The TFS4 system is generally similar to the TFS3 system and also comprises a modular injector 101 with two injectors 1, 1 ', the treatment chamber 42, and the evacuation device 62. Each injector 1, 1' further comprises a pressure plate. diffusion 95, 95 ', arranged at its output. Each diffusion plate 95, 95 'is designed to increase the gas flow near the adjacent walls of the injectors, to compensate for the lack of gas ejected in the zone of

Accordingly, the large gas wave in the process chamber has, at a distance from the outlet of the modular injector 101, a uniform velocity profile in a region 93 opposite to the connection zone. Figure 12A shows an exemplary embodiment 95-1 of the diffusion plates 95, 95 '. The diffusion plate 95-1 comprises openings 96-1 having constant diameters and a non-constant distribution, so that there are more openings near the edges of the plate 95-1 corresponding to the walls of the wall. injector, only in the center of the plate. For example, the center-to-center distance between the apertures varies from a minimum value S1 on the edges of the plate to a maximum value S2 in the center of the plate, where the apertures are further spaced. Figure 12B shows another embodiment 95-2 of the diffusion plates 95, 95 '. The diffusion plate 95-2 comprises apertures 96-2 having variable diameters and a constant center-to-center distance, arranged such that there are larger apertures near the edges of the plate 95-2. corresponding to the walls of the injector, in the center of the plate. For example, the diameter of the openings varies from a minimum value D1 near the center of the plate to a maximum value D2 at the edges of the plate. A third embodiment of the plates 95, 95 ', not shown, may include varying center-to-center distances between the apertures and varying aperture diameters. It will be noted that in Figs. 12A, 12B, the apertures of the diffusion plates 95-1, 95-2 have a similar arrangement on the right and left edges of the diffusion plates. This symmetrical arrangement allows

to increase the flow of gas on each edge of the injector outlets 1, 1 ', to compensate for both the absence of gas ejection in the connection zone 90 and the presence of non-adjacent side walls 91' of each side of the modular injector. Accordingly, the equivalent width of the output of the modular injector can be considered as the sum of the widths of each output, plus the sum of the thicknesses of the adjacent walls 91, plus the sum of the thicknesses of the non-adjacent side walls 91 '. In other embodiments, the apertures of the diffusion plates 95-1, 95-2 may have a non-symmetrical arrangement on the left and right edges of the diffusion plate. FIG. 13 schematically represents a top view in section of another embodiment TFS5 of a thin film deposition system according to the second aspect of the invention, which also provides for a better uniformity of the gas velocity profile in the treatment chamber and compensates for the presence of the connection zone 90. The TFS5 system comprises a modular injector 102, the treatment chamber 42, the evacuation device 62, and the connection zone 90. The modular injector 102 comprises two injectors 211, 211 'arranged so that they are adjacent and which are designed according to the first aspect of the invention, each injector comprising an expansion region 25 and a constriction region 24. Each injector 211 or 211' differs from the injector 11 or 11 'previously described in that the expansion and constriction regions are configured so that, at the output of the injector, the velocity of the gas near the paro is greater than the gas velocity near the center of the outlet, which also means that the gas flow near the walls is

greater than the gas flow near the center of the outlet. In a non-symmetrical embodiment of the injector 211, 211 ', the expansion and constriction regions may be configured such that the velocity of the gas is greater than in the vicinity of the wall which is adjacent to an wall of the other injector. FIG. 14 represents the profile C5 of the velocity V of the gas at the outlet of the injectors 211, 211 'of FIG. 13. The velocity of the gas is measured along an axis Y5Y5' which is perpendicular to the axis of propagation of the large gas wave, and at a determined distance d5 from the output of the modular injector, for example 5 mm from the modular injector. The speed profile C5 is substantially constant and has a variation of less than 10% between the maximum and minimum speeds over at least 90% of the width of the large equivalent output of the modular injector. A modular injector is susceptible to various other embodiments and applications. In one embodiment, a plurality of modular injectors, each comprising N parallel injectors, are arranged in a thin film deposition system that includes a conveyor belt on which substrates are arranged (in-line system) or a continuous roll of a flexible substrate (roller system). Whenever a substrate or part of the continuous substrate is in front of the output of a modular injector, one or more pulses of one or more gases are ejected onto the substrate. Such a system makes it possible to obtain a continuous deposition of thin layers on a series of substrates, with a higher production capacity. FIGS. 15A, 15B, 15C show various arrangements for supplying a gas to a modular injector 100, 101, 102. As it is desired to obtain

a uniform gas profile at the outlet of the modular injector, it is important to precisely synchronize the injection of gas into each injector, in particular when a pulsed process is implemented. In FIG. 15A, a single source of gas 81 is connected to the injectors 1,1 'or 211, 211' by means of a single valve 85. In FIG. 15B, a single source of gas 81 is connected to the injectors 1, 1 'by means of two valves 85, 85', one per injector. In FIG. 15C, a first gas source 81 is connected to the first injector 1 or 211 by means of a first valve 85. A second gas source 81 'supplying the same gas as the first gas source 81 is connected to the first gas source 81. second injector 1 'or 211' by means of a second valve 85 '. It will be apparent to those skilled in the art that these arrangements are applicable to modular injectors comprising N parallel injectors. More particularly, N parallel injectors can be controlled by a single valve. Moreover, despite the fact that the present invention has been described in connection with applications relating to thin film deposition techniques, it will be apparent to those skilled in the art that embodiments of an injector or modes of embodiments of a modular injector according to the invention can be used for other purposes, in different applications where it is necessary to inject a gas in a treatment chamber, for example for etching, diffusion, etc.

Claims (15)

REVENDICATIONS1. Modular injector (100, 101, 102) for injecting a gas into a treatment chamber (42), characterized in that it comprises at least two adjacent injectors (1, 211), each injector comprising: - an inlet for receiving a gas wave or a gas pulse; - a shaping section (2, 20) having left and right walls (91) diverging at a divergence angle (A1, A2) with respect to a propagation axis ( XX ', X2X2') of the gas, for expanding the gas in a perpendicular direction (YY ') to the axis of propagation, and - an outlet (22) for ejecting the gas, the modular injector forming a substantially equivalent large injector having a large equivalent output including the outlets of the adjacent injectors and expanding the gas over the large equivalent output. Modular injector according to claim 1, comprising a connection zone (90) extending between adjacent walls (91) of the injectors (1, 211), in which each injector comprises means (24, 95, 95 '). to eject the gas in the vicinity of the connection area with a higher flow rate than near the center of its outlet, to compensate for the lack of gas ejected in the connection area. Modular injector according to claim 2, wherein the injectors (1, 211) are configured such that the gas ejected by the modular injector through the large equivalent output has a velocity profile (C5) with a lower variation at 10% between the maximum and minimum speeds over at least 90% of the width of the equivalent large output at a specified distance from the outlet and the connection area. The modular injector according to one of claims 2 or 3, wherein each injector (1, 211) comprises a diffusion plate (95-1, 95-2) comprising a plurality of openings (96-1, 96- 2) for the passage of the gas, the openings being dimensioned (D1, D2) and / or spaced (Si, S2) from each other such that the injector ejects the gas in the vicinity of the connection zone (90) with a higher flow rate than near the center of its exit. The modular injector according to one of claims 2 or 3, wherein the shaping section (20) of each injector (1, 211) comprises at least one constriction region (24) in which a height of the section of shaping varies along an axis (YY ') perpendicular to the axis of propagation (XX') and has a first height (h2) close to the center of the shaping section and a second height (h3) to near the wall near the connection zone, the first height (h2) being lower than the second height (h3) in order to reduce the speed of the gas near the center with respect to the gas velocity towards the wall in the vicinity of the connection area. A modular injector according to claim 5, wherein the shaping section (20) of each injector (1, 211) has a first expansion region (25) in which the walls diverge at a first divergence angle (Al). ), and a second expansion region (26) comprising the constriction region (24), wherein the walls diverge at a second divergence angle (A2) smaller than the first divergence angle, to increase the velocity of the gas at adjacent the walls near the connection area with respect to the velocity of the gas near the center of the shaping section. The modular injector according to claim 6, wherein the first divergence angle (Al) varies and has a maximum value (Almax) at the end of the first region, and the second divergence angle (A2) is constant and less than the maximum value of the first angle of divergence. 8. Modular injector according to one of claims 1 to 7, having a curved forming section (113). 9. System (TFS3, TFS4, TFS5) comprising: - a treatment chamber (42), - at least one modular injector (100, 101, 102) according to one of claims 1 to 8, whose large equivalent output gives on the treatment chamber, and - at least one gas source (81, 81 ') coupled to the inlet of the injectors (1, 211) of the modular injector. 10. System according to claim 9, comprising at least two superimposed modular injectors arranged such that each injector (1, 211) of each modular injector has a common output with an injector of the other modular injector. 11. A method for injecting a gas wave or a gas pulse into a process chamber (42), comprising the steps of: - expanding the gas in a direction (YY ') perpendicular to a propagation axis (XX' , X2X2 ') of the gas, and - injecting the gas into the treatment chamber (42), characterized in that it comprises the step of injecting the gas into the treatment chamber (42) by means of a modular injector (100, 101, 102) comprising at least two adjacent injectors (1, 211), each injector comprising an inlet for receiving a gas, a shaping section (2, 20) having diverging left and right walls at an angle of divergence (Al, A2) with respect to the axis of propagation (XX ') of the gas, for expanding the gas in a perpendicular direction (YY') to the axis of propagation, and an output for ejecting the gas, the modular injector forming a large equivalent injector having a large equivalent output includes ant the outlets of the adjacent injectors and dilating the gas on the large equivalent output. The method of claim 11, wherein the modular injector comprises a connection area (90) extending between adjacent walls (91) of the injectors (1, 211), and comprising a step of configuring each injector to it ejects the gas in the vicinity of the connection area with a greater flow rate than the center of its outlet, to compensate for the lack of gas ejected in the connection area. The method of claim 12, comprising a step of configuring each injector (1, 211) so that the gas ejected by the modular injector has a velocity profile (C5) with a variation of less than 10% between maximum and minimum speeds over at least 90% of the width of the equivalent large output. The method according to one of claims 12 or 13, comprising a step of providing, in each injector (1, 211), a diffusion plate (95-1, 95-2) having a plurality of openings (96). -1, 96-2) for the passage of the gas, the openings being dimensioned (D1, D2) and / or spaced (Si, S2) from each other so that the injector ejects the gas in the vicinity of the zone connection with a higher flow rate than near the center of its output. The method according to claim 12, comprising a step of providing, in the shaping section (20) of each injector (1, 211), at least one constriction region (24) in which a height of the section layout varies along an axis (YY ') perpendicular to the axis of propagation of the gas and has a first height (h2) near the center of the shaping section and a second height (h3) near the wall of the shaping section near the connection area, the first height (h2) being less than the second height (h3) to reduce the velocity of the gas near the center of the injector by relative to the velocity of the gas near the wall near the connection zone (90).